Medical probes are widely used in the medical arts. For example, medical probes in the form of catheters are sometimes inserted into a patient's body during valve mapping and ablation procedures of the patient's heart. Catheters used for such procedures are typically comprised of metallic electrode tips of various shapes and sizes. Selection of the proper size by the physician depends largely upon the patient's anatomy, the procedure and physician preference.
Catheters of present manufacture are typically made with a platinum tip of a fixed length, ranging in length from about 4 mm, 5 mm, 6 mm up to about 10 mm. They are generally manufactured with a 7 French or 8 French diameter. The choice of overall length depends primarily on the length of the target tissue to be ablated. Present catheter tip shapes are hemispherical at the distal end, transitioning into a cylindrical portion proximal to the attached sheath. The hemispherical distal end is an aid to threading the catheter through blood vessels without interference, while the cylindrical section makes up the balance of the overall length.
After insertion of a platinum tipped catheter, mapping results may indicate the need for a larger (or smaller) platinum tip. Having to exchange catheters extends the time required to complete the procedure and places the patient at greater risk. Further, the 1 mm incremental sizing of the present catheters does not allow for fine control over the length of the ablated tissue. In addition, should the shape of the target tissue be highly convoluted, the cylindrical portion of the tip may not make uniform contact, causing the ablation to progress non-uniformly, making it difficult for the physician to achieve the desired result.